Stunning device for killing small animals or fish

ABSTRACT

Stunning device ( 1 ) for small animals or fish of 2 kg to 7 kg weight comprises pneumatically powered piston assembly ( 2 ) which includes an extendible piston. Support ( 3 ) for piston assembly ( 2 ) includes base member ( 4 ) and multi-component trigger ( 22, 23, 24, 26 ). Piston assembly ( 2 ) is positioned to define a space between base member ( 4 ) and head plate ( 21 ) for receiving the head ( 27 ) of the animal. When the piston is activated by head ( 27 ) contacting plate ( 22 ), it extends and strikes head ( 27 ) just behind and/or between the eyes with sufficient force to kill the animal with a shock to the brain, but without affecting the external appearance of the animal or fish. The piston extends only once and then retracts, and trigger ( 22, 23, 24, 26 ) is reset by removing head ( 27 ) from device ( 1 ).

This invention relates to apparatus which can be used to stun, orslaughter, small animals and fish. In particular, the invention relatesto pneumatically operated apparatus.

BACKGROUND FIELD

Processing of animals for food usually involves the initial slaughter ofthe animal. In the processing of larger animals such as cattle, this istypically done by a blow to an animal's head using a pneumatically- orcartridge-powered gun with a captive bolt or piston in place of aprojectile.

Processing of some fishes also requires slaughter as an initial step inthe process. For example, salmon are typically “stunned” by a blow tothe head before processing as food. In many instances, the blow isapplied with a simple club, there being no readily available apparatusfor the procedure. Smaller animals such as rabbits are similarly stunnedby a blow to the head, there again being no readily available apparatussuitable for use with animals of this size.

Any apparatus must be capable of delivering a blow to the head of ananimal or fish in such a way that stunning can be done humanely. Formost processing needs, the apparatus must also be capable of deliveringblows quickly and repetitively so that large numbers of animals or fishcan be processed.

Pneumatically powered apparatus is used for larger animals because itmeets the needs set out in the previous paragraph. However, suchapparatus is not suitable for use with smaller animals or fish. Smallerhand-held pneumatic devices are known—for example, pneumatically powerednail guns—but these are not suitable for use as a fish or animalstunning device because of their configurations. Such devices arenevertheless capable of delivering an adequate force.

SUMMARY OF THE INVENTION

The object of the invention is to provide a stunning device that can beused for the rapid and repetitive stunning of small animals or fish andthat utilizes pneumatic power.

In a broad format, the invention provides an animal or fish stunningdevice comprising:

a pneumatically-powered piston assembly comprising a piston retractablyextendable from an open ended cylinder included in said assembly;

a support for said piston assembly including a base member, wherein saidpiston assembly is positioned with respect to said base member to definea space between said base member and said cylinder open end forreceiving a head of an animal or fish, and wherein said piston canextend partially into said space; and

a trigger for activating extension of said piston when said trigger iscontacted by the head of said animal or fish when positioned in saidspace.

The operating principle of the stunning device according to theinvention is that that the animal or fish is killed by a blow to thehead administered by the piston of the device. The action is initiatedby insertion of the animal's or fish's head into the space between thebase member of the support for the piston assembly and the open end ofthe cylinder whereby contact with a trigger activates the piston. Thetrigger and cylinder are configured such that when the piston isactivated, it strikes the animal or fish just behind and/or between theeyes. This impact is sufficient to kill the animal or fish due to theshock to the brain.

A design feature of the device is that when activated, the pistonextends only once and then retracts. Removal of the animal or fishresets the trigger so that the device can be immediately used to stunanother animal or fish.

The piston assembly of devices according to the invention isadvantageously pivotally mounted to the support so that the distancebetween the base member and the open end of the cylinder can be adjustedto allow use with differently sized animals and fishes. The pistonassembly can be either fixed in a particular position or mounted suchthat some degree of movement is possible. This allows for automaticadjustment of the distance between the base member and the open end ofthe cylinder when differently sized individuals of the same species ofanimal or fish are to be slaughtered.

The mounting of the piston assembly to the support is typically suchthat the assembly can be demounted to allow cleaning of both components.Devices advantageously include guide plates to facilitate insertion ofthe head of the animal or fish into the space between the base member ofthe support and the open end of the cylinder. Preferably, the distancebetween guide plates at each side of the entrance to the device isadjustable. Advantageously, the entire device can be dismantled forcleaning of all components.

The support for the piston assembly advantageously comprises a planarbase member and planar side members. Alternatively, the support can be aframework of elongate members.

The pneumatic operation of the piston is typically effected byincorporating apparatus commonly known as a “nail gun” in the pistonassembly of devices according to the invention. As such guns aretypically capable of repetitive firing on activation, devices include amechanism which allows only a single extension of the piston. This willbe explained in greater detail below. However, it will be appreciated byone of skill in the art of the manufacture of such devices that thepneumatically-operated piston can be any suitable assembly including apurpose-built assembly.

Devices according to the invention can be used with small animals andare particularly suited for use with animals having a weight of 2 to 7kg. With regard to fishes, devices can be conveniently used with fishhaving a weight of up to about 7 kg such as salmon, trout and sea bass.Devices are most particularly suited for the stunning of salmon duringthe commercial processing thereof.

With devices according to the invention, animals or fish to be processedcan be rapidly and efficiently stunned with minimal risk of injury tothe operator. Furthermore, as triggering is effected by the head of theanimal or fish, both hands of the operator can be used to guide the headof the animal or fish into the device. An additional advantage ofdevices according to the invention is that the external appearance ofthe animal or fish is not affected by the killing process. This isparticularly important for sale of whole fish. The quality of fish isalso enhanced through more rapid and humane killing at the point ofharvest.

Having broadly described the invention, stunning devices will now beexemplified with reference to the drawings briefly described hereafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a device according to the invention.

FIG. 2 is a side view of the device shown in FIG. 1 with portions of thesupport for the piston assembly omitted.

FIG. 3 is a side view of another device according to the invention witha side member of a support assembly omitted to expose features of thedevice.

FIG. 4 is a side view of the support assembly of the device shown inFIG. 3 with components omitted to expose adjustment and releasemechanisms.

FIG. 5 is a detailed view of the adjustable mounting for a guide plate.

The same item number has been used for features appearing in more thanone drawing.

BEST MODE AND OTHER MODES OF CARRYING OUT THE INVENTION

The devices depicted in the figures are designed for the stunning ofadult salmon in the commercial processing thereof. However, it will beappreciated that with appropriate reconfiguration, the device can beadapted for use with other fishes or animals.

In FIGS. 1 and 2, there is shown device 1 comprising piston assembly 2and support assembly 3. To first deal with the support assembly, thiscomprises a planar base member 4 and planar side members 5 and 6 linkedby a cross-piece 7. In FIG. 2, side member 6 has been omitted so thatother features of the device can be seen. Support assembly 3 furtherincludes guide plates 8 and 9 that are adjustably fixed to side members5 and 6, respectively. Taking guide plate 9 as an example, fixing is viaa shaft 10 extending from an end of the guide plate, which shaft can belocked—typically via a threaded stud—into a collar 11 on side member 6.Base member 4 has fixed thereto a chin plate 12 which aids properpositioning of the head of the fish in the device as will be explainedbelow.

Turning to piston assembly 2, this is pivotally mounted to an axle 13extending between side members 5 and 6 to which rails at each side ofthe assembly are connected. One of these rails is item 14 of FIG. 2which is the rail furthest the viewer. The rail at the other side of thepiston assembly has been omitted to again allow features of the assemblyto be seen. Pivoting of piston assembly 2 is limited in movement awayfrom base member 4 by adjusting screw 15 in cross-piece 7 which contactsa tab 16 extending from the assembly. The minimum distance between openended cylinder 17 from which the piston of the piston assembly extendsand chin plate 12 is set by an adjusting screw 18 on the piston assemblywhich contacts a tab 19 projecting inwardly from side member 6.Adjusting screw 18 and tab 19 are shown in phantom in FIG. 2. It will beappreciated from FIG. 2 that with adjusting screws 15 and 18 set asshown, some pivoting of piston assembly 2 is still possible. That is,the piston assembly can pivot until tab 16 contacts the end of adjustingscrew 15. This allows adjustment of the distance between cylinder 17 andchin plate 12 to compensate for differently sized fish.

Cylinder 17 is essentially a sleeve mounted to a standard pneumatic gun20, the particular gun in the example being a Max Model No. NF510manufactured by Max Co., Ltd, Tokyo, Japan. The cylinder bore isindicated by the dashed lines in FIG. 2. The normal piston of the gun isreplaced with a sealed hollow stainless steel cylinder of about 100 mmin length. The end of the piston that extends from the cylinder has aconvex curvature to minimise damage to fish to be stunned which couldoccur with a piston having a flat extremity. The cylinder has mounted atits open end a head plate 21, with an appropriate aperture therein toallow passage of the piston, to further aid positioning of a fish in thedevice.

The trigger of device 1 comprises a contact plate 22 adjustably linkedto a pivot frame 23 which has a pushrod 24 extending therefrom forcontacting the activating button 25 of pneumatic gun 20. Pushrod 24 isalso acted on by a pneumatic pushrod 26 that disengages pushrod 24 frombutton 25 during operation of the device. This will be explained below.The position of contact plate 22 relative to the head 27 of a fishpositioned in the device can be set by adjusting the angle between thecontact plate and pivot frame 23 via adjusting screw 28. Pivot frame 23is biased to a pre-firing position as shown in FIG. 2 by spring 29 withthe position adjustable via a stop screw 30. The movement of pushrod 24is limited by a stop screw 31 and the pushrod is biased to the button 25contact position shown in FIG. 2 via spring 32. The piston assembly alsoincludes a five-way valve 33, the function of which will be describedbelow.

Device components such as the support assembly 3 are typicallyfabricated from a corrosion resistant metals material. A preferredmaterial is stainless steel. The support assembly of the exemplifieddevice has a length of about 370 mm, a width of about 185 mm, and aheight of about 205 mm. The pneumatic nail gun component 20 of thepiston assembly utilizes a normal air supply of 3.0 to 5.0 bar andtypically operates at 3.5 bar. The device is suitable for stunning fishsuch as salmon of 2 to 7 kg.

Operation of device 1 will now be described. To stun a fish, the head 27thereof is positioned in the space between head plate 21 and chin plate12 aided by guide plates 8 and 9. Movement of fish head 27 further intothis space ultimately results in the nose 34 of the fish meeting contactplate 22 which causes pushrod 31 to depress button 25 of pneumatic gun20. The piston then extends from cylinder 17 by up to about 30 mmthereby contacting the head of the fish. To prevent multiple firing ofthe gun (which would result in excessive damage to the fish), pushrod 24is stopped by stop screw 31 so that depression of button 25 is only toan initial (single fire) position. To allow immediate retraction of thepiston, pushrod 24 is disengaged from button 25 by pneumatic pushrod 26.The latter pushrod is activated by five-way valve 33 which senses a dropof pressure on firing of the gun to extend the piston with air beingdiverted to the pushrod. On removal of the stunned fish, contact plate22 and pushrod 24 are returned to the positions shown in FIG. 2 underthe action of springs 29, and 32, respectively.

The device is then ready for repetition of the foregoing procedure.

Device 1 is typically fixed to a horizontal surface, such as a benchtop, for use. However, it will be appreciated that the device can beused in any orientation.

In a variant of the device exemplified above, the pneumatic pushrod 26and five-way valve 33 can be replaced by a spring-extended double actingcylinder arrangement, thus avoiding the need for the five-way valve.

A variant of the device shown in FIGS. 1 and 2 is depicted in FIGS. 3and 4. With reference to FIG. 3, there is shown device 35 comprisingpiston assembly 36 and support assembly 37. The support assembly 37 isessentially the same as support assembly 3 of the device describedabove. Differences will be discussed below.

The piston assembly 36 includes a standard pneumatic gun 38 which inthis case is a Max Model No. NF352-ST/16-50 obtainable from Max Co.,Ltd, Tokyo, Japan. As this gun has a shorter barrel than the gun used inthe FIGS. 1 and 2 device, a sleeve 39 is mounted between gun 38 andcylinder 40, which cylinder 40 is similar to cylinder 17 of the FIGS. 1and 2 device. In the present case, the piston within cylinder 40 issolid and is connected to the piston of gun 38 by a solid rod not shownin the figure. The piston is grooved at its upper end, which groove hasan o-ring therein. The o-ring prevents slippage of the piston in betweenfirings of the gun. These details are again not shown in the figure.

The trigger mechanism of device 35, and the operation thereof, is thesame as the trigger mechanism of the FIG. 1 and 2 device. One differencein the operation of the gun, however, is that there is a supply of airto the body of gun 38 which air acts on the underside of the gun pistonto aid retraction of the piston after firing. This supply of air is froma branch line 41 of the air line 42 from five-way valve 43 to thepushrod 44 that is the equivalent of pushrod 26 of the FIGS. 1 and 2device. Consequently, after the gun is fired, there is a momentarysupply of air through line 42 and hence then to the gun body via line 41to aid cylinder retraction.

Device 35 further includes a pressure relieve valve 43 a which receivesair from a compressor. The device typically operates at 5.0 bar.

Device 35 also has a cover, shown in phantom as 45 in FIG. 3, secured tosupport assembly 37 by a spring clip on each side of the device, one ofwhich spring clips is shown at 46. The device has two guide plates likethose of the FIGS. 1 and 2 device but of the same length. One of theguide plates, 47 of FIG. 3, is hinged at its mid-point 48 with thedistal half 49 biased away from the centre of the device. When thedevice is mounted close to a wall with guide plate 47 on the side of thedevice closest the wall, the distal half 49 will contact the wallthereby closing any gap between the device and the wall. This prevents afish entering the gap between the device and the wall. The distancebetween the guide plates can be adjusted by the independent setting ofeach plate by a mechanism to be explained in detail below.

The angle of chin plate 50 of device 35 can be adjusted. The chin plateis pivotally mounted to the base 51 of support assembly 37 at 52. Aspring-loaded pin at the distal end of the chin plate is received in oneof the notches in a notched plate 53 on a side wall of the supportassembly.

Greater detail of adjustment mechanisms is presented in FIGS. 4 and 5.In FIG. 4, there is shown the base member 51 and a side member 54 ofsupport assembly 37. A support rail 55 for gun 38 is pivotally mountedat 56 to side member 54. The position of the gun is adjustable by virtueof adjusting screw 57.

To aid cleaning of the device, piston assembly 36 can be pivoted out ofsupport assembly 37 once cover 45 has been removed. To allow this, aboss 58 at the end of adjusting screw 57 can be released from a clasp 59therefor by virtue of a lever 60 acted on by an over-centre spring whichnormally retains the clasp about boss 58.

Adjusting screw 57 is adjacent side wall 54. The upper end of the screwhas a tee-piece 61. This tee-piece cannot rotate when the adjustingscrew is locked in position and cover 45 is in situ. Consequently,movement generated by operation of gun 38 does not alter the setting ofrail 55 and hence the position of cylinder 40 relative to base member 51(see FIG. 3).

When lever 60 is in the released position—which can only occur whencover 45 is removed—the lever lies across spring clip 62, the complementof spring clip 46 of FIG. 3. Consequently, the cover cannot be refitted.This prevents use of the device when adjusting screw 57 is not properlylatched. Spring clips 46 and 62 can be interlinked so that blocking ofonly one clip prevents operation of both clips.

A mechanism for the adjustable mounting of a guide plate to side member54 is shown at 63 of FIG. 4 and in more detail in FIG. 5, the latterbeing an exploded view. FIG. 5 shows a shaft 64 which projects from theend of the guide plate within the support assembly (see FIG. 3). Thisshaft is received in a boss 65 on a side wall of the support assembly.Shaft 64 includes a plurality of grooves 66 into one of which a springloaded plate 67 can drop when the shaft is in boss 65. This locks shaft64 in a particular position and thus sets the position of the attachedguide plate relative to the side walls of the support assembly. Liftingplate 67 via tab 68 allows repositioning of the shaft and hence theguide plate.

The device illustrated in FIG. 3 is operated in the same manner as theFIGS. 1 and 2 device.

It will be appreciated that many changes can be made to the stunningdevices and use thereof as exemplified above without departing from thebroad ambit and scope of the invention.

The term “comprise”, or variants thereof such as “comprising” or“comprised”, is used herein to denote the inclusion of a stated integeror integers, unless is the context of usage an exclusive interpretationof the term is required.

What is claimed is:
 1. An animal or fish stunning device comprising: apneumatically-powered piston assembly comprising a piston retractablyextendable from an open ended cylinder included in said assembly,wherein said piston assembly comprises a pneumatic gun with a sleeve assaid cylinder; a support for said piston assembly including a basemember, wherein said piston assembly is positioned with respect to saidbase member to define a space between said base member and said cylinderopen end for receiving a head of an animal or fish, and wherein saidpiston can extend partially into said space; and a trigger foractivating extension of said piston when said trigger is contacted bythe head of said animal or fish when positioned in said space, whereinsaid trigger comprises: a contact plate adjustably linked to a pivotframe having a first pushrod extending therefrom for contacting anactivating button of said gun; and a second, pneumatically operated,pushrod that disengages said first pushrod from said button immediatelyafter activation of said button; wherein said pivot frame is biased to apre-firing position and said first pushrod is biased towards said buttonto prevent refiring of said piston while said head of said animal orfish is in contact with said trigger.
 2. The device according to claim1, wherein said piston assembly is pivotally mounted to said support. 3.The device according to claim 2, wherein an adjustment mechanism isprovided to limit pivoting of said piston assembly or to fix said pistonassembly into a desired position relative to said base member.
 4. Thedevice according to claim 3, wherein said adjustment mechanism comprisesscrews that abut tabs projecting from said piston assembly mounting orsaid support therefor.
 5. The device according to claim 3, wherein saidadjustment mechanism comprises an adjusting screw on said pistonassembly support that engages a threaded boss on said support.
 6. Thedevice according to claim 5, wherein said boss can be disconnected fromsaid support to permit pivoting of said piston assembly out of saidsupport.
 7. The device according to claim 6, wherein said boss isconnected to said support via a clasp that can be opened for pivoting ofsaid piston assembly.
 8. The device according to claim 7, whereinopening of said clasp is via a lever acted on by an over-centre springthat normally holds said clasp closed.
 9. The device according to claim1, wherein mounting of said piston assembly to said support is via apair of parallel rails pivotally connected at an end of each rail tosaid support.
 10. The device according to claim 9, wherein said pivotalconnection is via an axle spanning said support.
 11. The deviceaccording to claim 1, wherein said support comprises a planar basemember and planar side members.
 12. The device according to claim 1,wherein an upright guide plate is provided at each side of side supportat said space defined by said base member and said cylinder open end.13. The device according to claim 12, wherein each said guide plate isadjustably mounted to said support for varying the distancetherebetween.
 14. The device according to claim 13, wherein saidadjustable mounting comprises a shaft extending from a guide plate thatis received in a boss on said support and is locked into position by athreaded stud in said boss.
 15. The device according to claim 13,wherein said adjustable mounting comprises an annularly grooved shaftextending from a guide plate that is received in a boss on said supportand is held in position by a backing plate that docks in a groove. 16.The device according to claim 12, wherein a distal portion of at leastone of said guide plates is hinged and biased away from said device. 17.The device according to claim 1, wherein said base member has a rampedmember in said space, and wherein said ramped member acts as a chinplate.
 18. The device according to claim 17, wherein the slope of saidramped member is adjustable.
 19. The device according to claim 1,wherein a spacer sleeve is positioned between said cylinder and said gunbody.
 20. The device according to claim 1, wherein said device includesa multiple-outlet valve for controlling supply of air to devicecomponents.
 21. The device according to claim 1, wherein an air linefrom a multiple-outlet valve is connected to said gun body to supply airto the underside of said gun piston to aid retraction of said cylinderpiston after firing of said gun.
 22. The device according to claim 1,wherein said piston includes an o-ring seal to prevent slippage of saidpiston after retraction thereof.
 23. The device according to claim 1,wherein a cover is provided over said device with an opening thereinthat coincides with the space between said base member and said cylinderopen end.
 24. The device according to claim 23, which further includes amechanism that prevents activation of said device when said cover isabsent.
 25. The device according to claim 1, wherein a plate is providedthat extends outwardly of the periphery of the open end of saidcylinder.
 26. An animal or fish stunning device comprising: an assemblycomprising a pneumatic gun connected to a piston within an open-endedcylinder, the gun being mounted to a frame comprising parallel rails; asupport into which said assembly is pivotally fitted via said rails, thesupport comprising a planar base member and planar side members, whereinsaid assembly is positioned with respect to said base member to define aspace between said base member and said cylinder open end for receivinga head of an animal or fish, and wherein said piston can extendpartially into said space; and a trigger for activating extension ofsaid piston when said trigger is contacted by the head of said animal orfish when positioned in said space, said trigger comprising a contactplate that is adjustably linked to a pivot frame having a first pushrodextending therefrom for contacting an activating button of said gun; anda second, pneumatically operated, pushrod that disengages said firstpushrod from said button immediately after activation of said button toprevent refiring of said piston while said head of said animal or fishis in contact with said trigger; wherein said pivot frame is biased to apre-firing position and said first pushrod is biased towards saidbutton.